In application against an adversary we can de-leverage him, that is; to remove what leverage he has and one stratagem is to isolate him, send him to Coventry for instance, meaning to isolate him from communication or assistance.
In these terms it means to cut him off from his friends but it could also be used in competition by ‘cornering’ him as in boxing or kick boxing when we press an opponent into the corner of the boxing ring. The smaller space affords him little room to move and therefore removes part of his army which are his techniques. If you face an opponent who is a good kicker but not too good at boxing you can virtually cut off his legs by trapping him in the corner where he has no space to use them and where you can leverage your position, having de-leveraged or isolating his weapons.
In warfare we can surround our opponents or separate one section from their army from another destroying this force before we move onto another section, gradually isolating and defeating the target section by section.
In wildlife programs we can often see where lions or some other type of predator will hunt a heard of buffalo harrying them one way and then another, then they target a weaker individual, probably a bull calf and work to separate it from the herd. Once they can separate it its leverage of safety within the herd is removed and it becomes an easy target.